坡地災害風險分級與土地調適策略擬定

災害對於臺灣山區的衝擊，將隨著氣候與環境變遷影響日趨嚴重，為儘早因應，本研究評估178個山坡地鄉鎮的坡地災害風險。透過災害風險因子篩選與分析、Jenks 自然斷點最佳化分級法，以鄉鎮區為最小單元，製作臺灣坡地災害風險地圖。本研究分析之坡地災害風險因子包括：降雨危害、綜合地文、歷史災害、崩塌比率、道路密度、人口密度與人類發展指標等7 項，依據GTZ 的方法分析得到坡地災害風險地圖。本文選定坡地災害風險等級4 與5 之地區，作為坡地災害高風險地區，提出災害風險調適建議。高風險區的調適方法，建議以國土測繪中心之土地利用調查成果為分析基礎，計算各災害風險區內與坡地災害相關之土地利用型態之面積與比例，依據各風險區內土地利用分析成果，探討各坡地災害風險區內之土地使用是否增加或降低災害風險。並建議因應氣候與環境變遷下之山坡地土地利用調適策略基準。

關鍵字

坡地災害；風險分析；土地利用；調適策略

並列摘要

In order to respond to the impact of climate and environmental change on Taiwan’s mountain region, this study ranked the slopeland disaster risk and calculated the land use area for 178 mountain towns. Seven indicators were selected in analyzing landslide risk, which are rainfall hazard, natural environment vulnerability (e.g., rainfall threshold criterion for debris flow, historical disaster frequency, landslide ratio, and road density), physicality vulnerability (e.g., population density) and socio-economic vulnerability (e.g., population with higher education, death rate and income). A slopeland disasters risk map could be made through mapping indicators and ranking risk values. The map pointed out towns with risk level 4 and 5, which are high slopleland disaster risk regions, and have high priority in reducing risk. Based on the landslide disaster risk map and the land use investigation dates which were provided by the National Land Surveying and Mapping Center in 2007, this study calculated how large the land use area with slopeland disaster risk is. With the above results, this study can suggest some appropriate land use adaptation strategies which are provided for reducing slopeland disaster risk under the impact of climate and environmental change.